(1) Field of the Invention
The present invention relates to a buoyancy system for an aircraft, and to an aircraft having such a buoyancy system.
Under such circumstances, the invention relates to the technical field of buoyancy systems enabling an aircraft to land on water and be stable thereon, and in particular making that possible for a rotary wing aircraft.
(2) Description of Related Art
Such a buoyancy system contributes to providing an aircraft with buoyancy and stability after landing on water. The buoyancy system may be used for example as a result of a forced landing on water (ditching), in order to enable the occupants to evacuate the aircraft. All aircraft that perform missions of transporting people over areas of sea should in principle be provided with such a buoyancy system.
Certification regulations also specify that an aircraft must be capable of landing on water and of remaining stable thereon when using its buoyancy system. Stability should be ensured for water surface states and wind levels that are defined in certification regulations.
Those water surface states are known as “sea conditions” and they apply to any liquid surface. The term “landing on water” thus covers an aircraft “landing” on any free water surface, whether at sea, or on a lake, for example.
The buoyancy system may comprise floats that are deployed either by the pilot and/or the copilot, for example, or else by automatic triggering, in particular by using one or more immersion sensors. The floats may comprise bags that are inflatable by explosive or electric deployment means, for example.
By way of example, Document EP 0 193 265 B1 discloses a buoyancy system having inflatable buoyancy bags that are fastened to landing gear.
Document US 2003/0057322 also discloses a buoyancy system attached to landing gear.
A buoyancy system may also comprise structural floats that are not inflatable.
Thus, buoyancy systems are known that are provided with floats fastened to an aircraft fuselage.
Document JP 61-171699 and Document US 2003/0057322 disclose a buoyancy system attached to a helicopter skid.
Document U.S. Pat. No. 3,467,343 describes a buoyancy system having vertical floats that are inflated with compressed air. The floats are provided with wheels operated by hydraulic actuators.
Document JP 2010 064697 (Nat Univ Yokohama) describes an aircraft having a fuselage and two floats. Resilient means serve to move the floats outwards.
Document U.S. Pat. No. 2,271,065 (Dornier Jr Claudius) describes an aircraft having two retractable floats that move away from a fuselage before landing on water.
Also known are Documents U.S. Pat. No. 3,321,158 and U.S. Pat. No. 3,240,449.